1. Field
The present disclosure relates generally to acoustic events and, in particular, to arrays used to detect acoustic events, such as sonic booms. Still more particularly, the present disclosure relates to a method and apparatus for determining the direction of arrival of a sonic boom detected using a microphone array.
2. Background
Microphone arrays are oftentimes used to detect acoustic events. Many different configurations may be possible for a microphone array. When an acoustic event is detected using a microphone array, it may be desirable to determine a direction of arrival of the acoustic event.
A sonic boom is an example of an acoustic event. A sonic boom is the sound associated with the shock waves created by an object traveling through the air faster than the speed of sound. For example, certain types of aerial vehicles may be capable of traveling faster than the speed of sound, thereby creating a sonic boom.
The direction of arrival of a sonic boom may be the direction in which the sonic boom is propagating when the sonic boom arrives at the microphone array. The direction of arrival of an acoustic event, such as a sonic boom, may be defined by an azimuth angle and elevation angle relative to the microphone array. In some cases, depending on the type of acoustic event and type of object that created the acoustic event, the direction of arrival of the acoustic event at the microphone array may then be used to identify other information about the acoustic event or the object that created the acoustic event. For example, the direction of arrival may be used to infer the location of the object relative to the microphone array, information about the propagation path of the acoustic event, or other types of information.
The direction of arrival of the sonic boom may be determined using some currently available beamforming techniques. However, the amount of time and processing resources needed to determine the direction of arrival of the sonic boom using these currently available beamforming techniques may be greater than desired. Further, some currently available beamforming techniques may be able to determine the azimuth angle of the object more quickly but may be unable to determine the elevation angle of the object. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.